Apparatus for the production of artificial filaments



P 27, 1949. J. E. BLUDWORTH YET AL 2,482,834

APPARATUS FOR THE PRODUCTION OF ARTIFICIAL FILAMENTS original-Filed March 4, 1944 INVENTORS.

JOSEPH E .BLUDWORTH CANHELD HUTSON a ATTORNEYS.

Patented Sept. 27, 1949 Canfield Hutson, Cumberland, Md., 'assignors to Celanese Corporation of America, a corporation of Delaware Original application March 4. 1944, Serial No.

525,036.- Divided and this'application'April 2, I 1946, Serial No.-659,030

invention r'elates to the production of artificial filaments by spinning operations; and relates more particularly to the preparation by wet-spinning processes of artificial filaments havinga basis of an organic derivative of cellu-' lose.'such as cellulose acetate, or other filament forming material, from solutions of said filamentforming materials in a volatilesolvent. This application is a division of our application Serial No. 525,036, fil'ed March 4, 1944, which has now issued as Patent No. 2,425,782.

' Artificial filaments or threads having a basis of an organic derivative of cellulosasuch as cel lulose acetate, or othenfilarnent-forming material, are usually preparedbyextruding a solu-. tion'of cellulose acetate in acetone under pressure through a jet or spinneret into an atmosphere of warm or hot-air or other evaporative medium circulating through a spinning cabinet. The filaments become solidified'on evaporation of the volatile solvent and are then associated to form a thread which is wound into a package Then, too,- the valuable solvent must be recovl ered from the air by means of an expensive solvent recovery system. To avoid these disadvantages, it has been proposed to prepare such arti-' ficial filaments by Wet-spinning methods wherein a solution of cellulose acetate in acetone or other solvent is extruded through a jet or spinneret into anraqueous coagulating bath. Various agulating baths have been suggested with a view toward-producing strong and elastic filaments.

Among :the various coagulating baths which have been mentioned are aqueous baths. containing thiocyanates and aqueous baths containing vari-. ous organic compounds -which are solvents. or; latent solvents tor the filament-forming cellulose acetate material. These coagulating baths yield artificial filaments having somewhat improved properties over those obtained by extrusion into av water, bath free of inorganic salts or organic solvents. However it has not been possible, hereto fore, by the usual wet-spinning operations, to form said filaments at spinning speeds greater than 60 I to 100 meters per minute, which speeds do not approach the usual commercialspinning speeds achieved by dry-spinning, and, consequently wetspinning is comparatively.uneconomical.

It'is an important object of this invention to provide improved apparatus for the spinning of artificial filaments having a basis of .anbrganic: derivative of cellulose, such as cellulose acetate, or other filament-forming material- Another object of this invention isthe produc tion of improved apparatus for the wet-spinning of artificial filaments having a basisof an organic derivative of cellulose or. other filament-forming material at speeds substantially higher than those which have heretofore beenpra-ctical'on a commercial scale. f 7 Other objects of this invention will appear hereinafter from the following detailed "descrip'-' tion and the accompanying drawing.

Fig. 1 is a perspective view ofourInovel spin} ning' apparatus for the production of artificial filaments by wet-spinning methods, f

vent through a jet or'spinneret into an enclosed chamber filled with a fog or mist, comprising droplets of a liquid in which the volatile solvent employed is soluble but in which the filamentforming material'is insoluble, and then, after. solidification of the filaments in the chamber passing the solidified filaments into a, bath of the.

liquid placed outside of the chamber... The volatile solvent evaporated from the filaments in the fog-filled chamber is absorbed by the fog or mist andthesolvent remaining in the solidified filaments after they leave the chamber is washed out in the liquid bath. After leaving the liquid: bath, the filaments are dried in warm air, or other;

suitabledrying media. The filaments may then spinning chamber and then passing the solidified: I filaments through a water bath or solution prior.

to forming the yarn package.

Preferably, the solution of cellulose acetate in the acetone is heated prior to extrusion. Suitable heating means may be provided and the temper-- ature at which it is extruded "maybe ifcm-80 i F. to 206 F. The temperature of the water bath may be any temperature above the freezing point,

felt, rubber or other material. The volatile solvent which is evaporated from filaments 9 is dissolved by the water mist or fog which condenses in cabinet 3 and drips into trough I6. The solvent remaining in the filaments 9 is washed out during the pas-sage of the filaments through the water bath. Suitable means (not shown) are provided for circulating the water in trough 16 whereby the solvent-laden water is continuously or intermittently removed and replacedwith fresh water free of solvent. The liquid removed from trough I6 is then sent to a suitable solvent recovery system where the organic solvent is separated from the'water, concentrated and then employed again to form a spinning solution. Suitable'yarn finishes may also be added to the water "bath, if desired.

of water and may vary from temperatures'as low as 33 F. up to 170 F. or more, but preferably the temperature is maintained at lower than the usual room temperatures. The water sprayed and atomized in or into the cabinet to form the fog or mist of water droplets through which the filaments pass may be any'temperature above the freezing point ofwater or even be'preheated, but preferably the temperature is from about 33 to 60 F. so that'the temperatures of 40 Fto 60 F. are maintained in the cabinet.

In order to further illustrate our'invention, reference may be had to the'accompanying drawing.

Referring now to the drawing and'more particularly to Fig. 1, reference numeral '3 indicates an enclosed cabinet of cylindrical or other'shape provided at '4 and "5 with suitable spraying or atomizing nozzles adapted to form, a'finelydivided fog or mist when water isforced through said nozzles under pressure. At the top of cabinet/3 is tube 5 connected to a candle filter 1 which carries at the lower end thereof a spinning nozzle or jet 8. through whichthe spinning solution is continuously extruded underpressure to form filaments 9. To heat the spinning solution prior to extrusion, candle filter I is surrounded bya heating jacket "i adapted to receive a circulating fluid heating medium H, such as "steam, hot water; heated'oil' or the like. The'fluid medium'l I enters jacket Ill through a pipe i2 and is discharged througha pipe l3.

Filaments 9 traverse a vertical paththroug'h the fog or mist in cabinet 3 and leavethrough a suitable opening 14 at the'base' of the cab inet, 3. They are then taken up by arotatin'g "feed roller. l'5,.rotating in the direction shown, which is partly submerged in a trough 16 containing water or. other non-solvent liquid. ,After making several revolutions about rotating feed roller I5, 'fila-' ments 9 pass around an auxiliary rotating feed roller or thread guide 'i'l, again around roller and thenlthrough a suitable guide [8' to be taken up in any'suitablemanner to format yarn package IS. The feed roller. 15, when rotating and par tially submerged in trough i3, agitates and imparts motion to the water. The depth and quan=. tity of Water which adheres or clings to the out-.- side circumferential surface of the revolving. roller 15, is proportional'to the speed of rotation. Athigher speeds water tends to be flung from the'wetted surface of the roller l 5Eby centrifugal force. In orderto regulate the quantity of water retained on the roller surface and the throw-off, there is provided an adjustable doctor: blade, deflector or wiper E-a, with a suitable facing of In the-embodiment of our invention shown in Fig. 2, the filaments 9 are extruded into the cabinet-"3 through jet 8 and, after traversing through timing or mist of water droplets, the filaments are passed directly into the water bath or solution contained in trough 16. The running filaments '9 pass under guides 20 and 2| which are submerged beneath the liquid, then over guide 22 and around driven feed roller"23. The filaments leaving roller "23 are passed'to suitable winding means (notshown) are then'taken up to form a suitable yarn package Hi. In this modification. of our invention, a somewhat increased 'path through the liquid bath in trough l6 is'provided and the feed roller is outside of'the bath instead of bein submerged therein. In lieu ofdirectin'g' the filaments in a vertical path through cabinet 3, they may, of course, be caused to traverse a substantially horizontal or semi-'horizontal-path, asshown in Fig. 3, .by suitably positioning cabinet 3, or they may enter into the aqueous medium at any other desired angle. Entering the filaments into the waterbath at an angle allowsfor'a more extended path through the liquid bath;

While our invention has been more particularly described in connection with the production of filaments having a basis of cellulose acetate from soluti'ons'thereof in acetone, itis 'to be unders't'oodjof course, that the filament-forming material employed may be any other organic derivative of cellulose or any other suitable filamen-t-forming material. Suitable organic derivatives of cellulose are, for example, cellulose esters, such as cellulose propionate or cellulose butyrate, mixed esters such as cellulose acetatebuty-rate -or cellulose acetate-propionate, or cellulose ethers, such as ethyl cellulose or benzylcellulose. Other materials from whichfilaments may be formed by extrusion of said filamentforming material in a volatile solvent may "also beemployed inthe preparation of artificial fila-. ments by our novel wet-spinning process. :As, suitable volatile solvents which "may be employed in-lieu of acetone there may be mentioned ethylethEIi-QlCOhDL di-chlor-methane, sulfide, .et'c., while suitable liquids in which the volatile solvents are soluble but in which-the filament-for-ming material is insoluble and which maybe employed to form the mist-and the'li-quid'f bath are methanol, hexane; etc.

-It isto be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be;

carbon di-J 1. Apparatus for the production of artificial filaments from filament-forming materials by wet-spinning processes, comprising a spinning chamber and a spinning nozzle in said chamber for the extrusion of artificial filament-forming material, means for spraying a mist of liquid droplets into said chamber and means contiguous to the exit end of said spinning chamber for supplying non-solvent liquid to said filaments,

ber for holdin non-solvent liquid to be applied to said filaments, the construction and arrangement being such that the exit end of the spinning chamber is at least partially submerged in said non-solvent liquid whereby the filaments come into immediate contact with the non-solvent liquid, and means spaced from said receptacle for taking up said filaments.

JOSEPH E. BLUDWORTH.

CANFIELD HUTSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,949,604 Dreyfus et a1. r Mar. 6, 1934 2,068,538 Dreyfus et a1 Jan. 19, 1937 20 2,081,171 Dreyfus May 25, 1937 2,161,354 Imray et al June 6, 1939 

